Maritime transportation accounts for 90% of the world’s trade and about 3% of its emissions. For Japan, it is even more vital, sustaining imports of food and fuel, and exports of machinery on which the nation’s economy stands. Sea transport carries 99% of Japan’s trade.

Demand for shipping has historically grown faster than the global economy, but solutions to clean up the industry’s carbon footprint have been slow to reach fruition. The International Maritime Organization (IMO) has a greenhouse gases (GHG) reduction strategy that calls for a cut in CO2 emissions of 20-30% by 2030 (compared with 2008 levels), 70-80% by 2040, and virtually zero by 2050. Which technologies and fuels can help meet these targets is unclear.

In Japan, ammonia has emerged as a compelling – if challenging – alternative to heavy fuel oil. Ammonia contains no carbon, meaning that when burned it emits no CO2. In theory, widespread use of ammonia could enable zero-carbon voyages.